Biomagnetic instrumentation using Superconducting Quantum Interference Devices (SQUIDs) has great potential for noninvasively monitoring the heart, brain, nervous system, and muscles. The widespread application of SQUIDs has been limited by the cost and complexity of liquid helium cryogenics and the requirement for very expensive magnetically shielded rooms. These problems can be handled by utilizing SQUIDs based on liquid-nitrogen cooled high temperature superconductors (HTS) and new noise cancellation techniques that include the patented Three SQUID Gradiometer concept. We will focus on one particularly important application, namely, fetal heart rate monitoring. In Phase I we demonstrated the effectiveness of the TSG in canceling the environmental noise and established that it has the fundamental performance characteristics needed to measure small magnetic signals in a magnetically noisy environment. In Phase II we propose to build a TSG-based gradiometer with more sensitive HTS SQUIDs and demonstrate that it has sufficient sensitivity to detect fetal cardiac signals. At the end of Phase II we plan to have the gradiometer ready for development into a commercial product by our collaborator Biomagnetic Technologies Inc. (Bti), a leader in developing and commercializing biomagnetic instrumentation. In addition to Bti, this project will benefit from Quantum Magnetics~ close collaboration with IBM. PROPOSED COMMERICIAL APPLICATION Successful development will lead to a new class of inexpensive, portable instruments for rapid, contactless evaluation of electrical functions in the body. The main initial application is fetal heart rate monitoring which offers unique capability for monitoring fetal distress. Other applications include monitoring fetal arrhythmias; potential adult applications include monitoring digestive function and diagnosing gut ischemia, measuring currents of injury, and detecting cardiac dysrhythmias in emergency medicine, search and rescue, and battlefield triage.